Damper



June 23, 1942. IT. FLETCHER DAMPER Filed Sept. 20, 1940 lNVENTOR THOMAS FZfTCl-IFR ATTQRNEYS Patented June 23, 1942 DAMPER.

Thomas Fletcher, Ravenna, Ohio, assignor to The A. C. Williams Company, Ravenna, Ohio, a corporation of Ohio Application September 20, 1940, Serial No. 357,574

3 Claims.

This invention relates to dampers for air ducts, flues, chimneys, stove pipes, etc., hereinafter collectively referred to as stove pipes having a substantially circular cross-section at the place of installation of the damper.

One object of the invention is a self-centering damper which may be supported in the stove pipe on a spindle which for the support and operation of the damper is required to extend through one side only of the stove pipe.

Another object of the invention is a self-centering damper which my be mounted in the stove pipe with the maximum of ease and convenience withoutthe necessity of flattening the stove pipe or of requiring a modification in the curvature thereof.

Another object of the invention is a self-centering damper of low manufacturing cost.

Other objects of the invention will be apparent as this specification progresses. I have selected for purposes of illustration of the invention a cast iron damper mounted in a sheet steel stove pipe and have so shown the invention in the drawing hereof. Such selection and showing, however, should be understood as purely illustrative and not limitative upon the scope of the invention.

In the drawing, Figure 1 is a front elevation of a damper mounted in a stove pipe shown in cross-section, said damper being in fully closed position; I

Fig. 2 is a side elevation of the damper of Fig.

1 mounted in the stove pipe which as in Fig. 1 is shown in cross-section, said damper being in fully open position; and

Fig. 3 is a detail in plan of the inside bearing of the damper.

The damper comprises a circular damper plate 5 substantially fiat and as thin as practical and of a diameter somewhat smaller than that of the stove pipe 6 in which it is intended to be mounted, this difference in diameter of the damper plate and stove pipe being such as to provide for the desired passage of air, fuel gases, and/or smoke between the periphery of the damper and the stove pipe inclosed position of the damper. If desired additional passageway for the said air, fuel gases, and/or smoke may be provided by a suitable opening I at the center of the damper plate.

The damper is provided with a spindle H] for supporting the damper plate 5 in the stove pipe and for moving the damper plate to any desired position therein from fully open to fully closed position. This spindle is preferably circular in cross-section. The spindle is provided at one end externally of the stove pipe with a suitable handle II and at the other end terminates about .midway of the damper plate in a sharp point l2. The spindle is removably attached to the damper plate by means of a bend or projection 13 which may be seated in a cooperating tapered depression I4 in the damper plate, the

parts being so constructed and arranged that the spindle may be removed from the damper plate when the bend or projection is rotated out of engagement, with the depression. Toward the center of the plate this spindle passes between oppositely disposed centering portions I5 and I6 cast into and as a part of the damper plate. The inside or pointed end of the spindle I2 may terminate at about the center of the damper plate in the opening I.

At the edge of the damper plate 5 where the spindle is mounted the damper plate is formed with a bearing 20 integrally connected with the damper plate 5 and preferably cast therewith. This bearing 20 has a bearing surface which is curved substantially in accordance with the curvature of a segment of a sphere struck from a center substantially coincident with the center of curvature of the cross-section of the stove pipe where the damper is mounted. The bearing is provided with an opening 2| of a width substantially equal to the diameter of the spindle with sufficient clearance to permit the bent or projecting part [3 of the spindle to be moved through the said opening, said opening being radial in direction and of such depth that when the spindle is in locked position the spindle passes substantially through the center of the bearing.

The bearing 20 is held in contact with the interior surface of the stove pipe 6 by resilient means such as a compression coil spring 25 mounted on the spindle between two thimbles 26 likewise mounted on the spindle, one of said thimbles being in contact with the handle ll of the damper and the other in contact with the stove pipe 6.

To mount the damper in the stove pipe the spindle is removed from the damper by rotating its bend or projection l3 out of locking engagement with the depression I and withdrawing the spindle from the damper plate 5, the bend or projection passing through the opening 2| in the bearing 20. The stove pipe is then pierced with the pointed end l2 of the spindle or otherwise provided with a suitable opening for the spindle on one side only at the place where it is desired to mount the damper. The damper plate is then inserted into the stove pipe and held in position with the opening 2! in the bearing 20 in line with the hole made in the stove pipe. The spindle is then inserted through the hole in the stove pipe, through the bearing and between the centering portions l and Hi, the spring 25 being depressed, and there turned so that the bend I3 of the spindle is in line with the tapered depression I4 in the damper plate. The handle H is then released and the spring 25 draws the bend l3 into firm engagement with the depression I and holds the bearing 20 in seating engagement with the inside of the stove pipe 6.

As the bearing 20 has its surface curved .substantially in accordance with the curvature of a segment of a sphere struck from a center substantially coincident with the center of curvature of the cross-section of the stove pipe where the a damper is mounted, it will be seen that this bearing surface maintains complete contact with the curved surface of the stove pipe for all positions of the damper in the stove pipe-open, closed and intermediate. By reason of this the damper is self-centering in the stove pipe in all of its said positions.

To remove the damper from the stove pipe it is only necessary to compress the spring 25, rotate the bend I3 of the spindle out of locking engagement with the depression l4 and then withdraw the spindle from the damper plate and from the stove pipe, thereafter removing the damper plate from the stove pipe manually.

The foregoing detailed description has been given for clearness of understanding and no undue limitation should be inferred therefrom.

I claim:

1. In a damper, the combination of a damper plate, a removable spindle mounted in looking position therein, a handle attached to the spindle for rotating the damper plate and a stove pipe in which the damper is mounted for rotation, said stove pipe being substantially circular in crosssection; a large bearing on the damper plate, the bearing surface of which is curved substantially in accordance with the curvature of a segment of a sphere struck from the center substantially coincident with the center of curvature of the cross-section of the stove pipe, said bearing being provided with a central opening through which the spindle passes to locking position; and means for maintaining the bearing in rotatable position against the inner face of the stove pipe; the construction and arrangement being such that the damper is substantially self centering in the stove pipe in open, closed and intermediate positions with the spindle passing through only one side thereof.

2. In a damper, the combination of a damper plate, a removable spindle mounted in looking position therein, a handle attached to the spindle for rotating the damper plate and a stove pipe in which the damper is mounted for rotation, said stove pipe being substantially circular in crosssection; a large bearing on the damper plate, the

bearing surface of which is curved substantially in accordance with the curvature of a segment of a sphere struck from a center substantially coincident with the center of curvature of the crosssection of the stove pipe, said bearing being provided with an opening extending from the outside substantially to the center thereof through which the spindle passes to locking position substantially central of the bearing; and resilient means for maintaining the bearing in rotatable .position against the inner face of the stove pipe; the construction and arrangement being such that the damper is substantially self centering in the stove pipe in open, closed and intermediate positions with the spindle passing through only one side thereof.

3. In a damper, the combination of a damper plate, a removable cylindrical spindle mounted in looking position therein, a handle attached to the spindle for rotating the damper plate and a stove pipe in which the damper is mounted for rotation, said stove pipe being substantially circular in cross-section; a large bearing on the-damper plate, the bearing surface of which is curved substantially in accordance with the curvature of a segment of a sphere struck from a center substantially coincident with the center of curvature of the cross-section of the stove pipe, said bearing being provided with an opening extending from the outside substantially to the center thereof through which the spindle passes to locking position substantially central of the bearing, said opening being of a Width substantially equal to the diameter of the spindle; and resilient means for maintaining the bearing in rotatable position against the inner face of the stove pipe; the construction and arrangement being such that the damper is substantially self centering in the stove pipe in open, closed and intermediate positions with the spindle passing through only one side thereof.

THOMAS FLETCHER. 

